Drifting and relief valve



March 23, 192s.

H. F. RlPKl-:N

DRIFTING AND RELIEF VALVE Filed August 24, 1921 gaz/a 'jygiei his om v \\\\\.Jlu E ....I `lll 11:.

Patented Mar. 23, 1926.`

UNITED @murine nim antler vanvn Application filed August 24, 1921. Serial No., 1l 9 5,027.

To all? -waom t may concer/n Be it known that I, HUGO F. RiiiinN, a citizen of the United States, residing r at Minneapolis, in vthe county of Ifennepin and State -of lllinnesotm have invented certain new and useful Improvements in Drifting' and Relief Valves, of which the following is a `specifi-cation.

My invention relates to improvements in drifting and relief valves forreciprocating steam engines, and especially for those eniployed in railway locomotives using superlieated steam. The present invention is animproveinent intended for use in the construction of valves of the typeshowii in the United States Patent, No. 1,280,8l8, issued to meOctober 8, 1918, and hasfor its object, to provide means whereby the piston willjbe positively held to its seat, in its normal inactive position. It will benot'ed, that in the valve described in the above named patent, piston ring friction, and the weight of the piston itself is wholly relied upon to lhold it to its seat. To prevent accidental movementv of saine, due to inaccurate workmanship, ,and add; to its stability, in its normalseated po sition, to secureat all timespositive,uni

Y form action, I employ novel and eective means, whereby the descendingpiston, by its movement from operative to inoperative position, develops an annular chamber, which opens to coi-mnunication `with a constant live steam area, as the piston approaches its seat. the piston being provided with a relatively small pressure receivingl surface or shoulder within the developed chamber, the pressure on said shoulder serving to hold fit on its seat. i

More particularly, the invention consists in the construction, combination and arrangement of parts hereinafter described and claimed.

'In ther drawings:

Figure l is a vertical longitudinal sectional view through the centerof the cylinder and steam chest of a reciprocating engine with my improved valve shown in full.

Figure 2 represents a vertical sectional view through the center of the valve body, showing the valve proper in its normal position and Figure 3 is a similar viewgshowin ,gthe valve in operating position. y

rihe general operation of the valve shown,

is substantial]Tv similar-to that of the `valve forming the subject of the patent mentioned in the foregoing, with the exception of 4the auxiliary steam pressure on the piston in its downwardmovement. 1

In the `diawings A represents the cylinder of a reciprocating engine, B the piston working thereon, and C the steam chest in which works the valve piston I), allof usual type.

My improved valve comprises 1va cylindrical casing or valve body 2, the interior of which is open to communication with one end of the interior of the cylinder through the medium ofthe threaded nipple 3 at the lower extremity of the valve body, kthe interior of the. nipple leading into a duct l which latter extends around a bushingat one end of the steam chest to the cylinder port 5 on that side of the piston B.

The compressed air or steam in that end of the cylinder will thuspass through the l duct l, into the lower part of the valve casing, under the valve, hereinafter described.

Leading from the topof the casing` 2 tothe main steam supplypipe or conduit E, and communicating with the interior 'thereof is an auxiliary steamsupply pipe 6 communieating` with the interior in the top of the casingI 2, the casingbeing provided with a live steam inlet 7 at oneside thereof, projecting laterally therefrom, which inlet is open to communicationl with the pipe 7a which is connected with a source of live steam supply such as the dome of the boiler.

Woi'lring within the valve casing 2 is a sliding` hollow valve `piston '8,4 having an inset bottom, forming an inverted cuplike lower portion. The upper 'portion of the piston 4is of enlarged diameter, forming at the point where it joins the lower portion, a circular 'flat' seat oi" shoulder 9, which seats on a co-operatino' shoulder 9 in the casing.

yThe piston maytherefore be termed a differential piston as it has a top and bottom of different diameters and main and auxiliary bottom surface. A row of spaced oblong ports l() surround the piston and pierce the peripheral wall of the upper poi'- tion thereof, suitable piston rings i8 and i0k beinol orovided res aectivel above and Ve l t l Y below,` the ports and located immediately adacent thereto toprevent leakage.

'A' lbusliingll adapted to slidably receive the piston 8, `forms an inner cylindrical wall the port 5, andA in the duct il.

for an annular groove cast in the wall of the casing, thereby forming the annular walled-in chamber portion 11 of the inlet 7, the latter being open to communication with the interior of the supply pipe 7a. This inner' wall of the inlet chamber is pierced by a circumferential row of ports 13, which are arranged to register with the ports 10 when the piston 8 is slid upward against the shoulder 14 in the casing.

Leading downwardly from the annular Vchamber portion, of the inlet 7, and from the casing wall, and opening into the iuterior of the casing at a point abovethe shoulder 9L (whereon the piston normally rests) by means of the port 15 is a duct 15, the port being guarded against lealiage by the rings 10 and 10 carried by the piston. The lower portion of the piston is of reduced diameter as at 8 owing to the shoulder 9, and is provided with the packing ring 9 to prevent steam from the steam chest from passing between the piston and the casing at this point.

Opposite the port 15, piercinel the wall of the casing at a point in the shoulder 9a is a vent 16 which acts as an exhaust and may open to the atmosphere, or be connected with the exhaust chamber as shown in Figure 1.

In operation, when the throttle valve, not shown is closed, the pressure in the conduit i1 mediately thereafter falls or is reduced, while the piston B (Fig. 1) will travel, (while the engine is drifting), to the right, compressing the gases before it, and producing a back pressure in the cylinder, in

pressure is communicated to the bottom of the valve piston 8, causing it to be lifted from its seat 9a in the casing and slid upwardly until it abut-s against the shoulder 14. )When in this position, as hereinbefore stated, the ports 10 and 13 are in register, thereby establishing communication between the interior of the pipe 7 and the interior of the casing.

Live steam from pipe 7 will now pass (as indicated by the arrows Fig. 1) through the inlet into the casing 2 above the vavo piston and through the medium of pipe 6 and conduit E enter the steam chest and cylinder, where it will prevent any vacuum forming tendency behind the piston because the pressure in the conduit (when the throttle is closed) is counter-acted only by the back pressure generated by the piston and the friction of the packing rings (on the valve piston) and which cannot be relied upon to maintain the valve piston in operating position and prevent a Vfluctuating movement thereof. The' port 15 and the shoulders 9 and 9a, respectively, of the valve piston 8 and the casing are provided to permit steam to enter the port 15, and thence This backl enter the cavity formed between said shoulders when the piston is moved upward to hold the piston 8 in operating position.

As the valve piston 8 is automatically raised, (by pressure generated in the cylinder), it uncovers the port 15 to admit live steam to the annular cavity formed between the seat 9 and its cooperating shoulder 9a in the casing (when the valve piston is moved) the steam pressure in the cavity serving to regulate the pressure which causes the downward movement of the piston as will be hereinafter explained.

The vent 1li admits air to the cavity to prevent creation of a partial vacuum therein (when the valve piston is raised) which would otherwise tend to oppose the back pressure generated in the cylinder. lt also acts as a restricted outlet for the inrushing steam, the vent 1G being appreciably smaller than the inlet port 15, resulting in back pressure in the cavity, whereby the piston is controlled to descend only when there is excessive steam pressure above it, which occurs when the engine is drifting very slowly or actually comes to rest.

)Vlien the engine comes to rest the valve piston descends, covering the ports 10 to cut olf the live steam supply and then covering the port 15 from which point it will slowly descend, riding on the air or steam pocleted in the cavity which is now expelled through the restricted vent 16 by the descending piston, whereafter the piston valve comes to rest on its seat.

The foregoing descriptive matter relating to construction and operation is found in my prior patent hereinbefore mentioned, and the subject of my present invention may now be described as follows.

1n my prior patent, the weight of the piston and piston ring friction, are relied upon to hold the .valve 8 to its seat 9. ln the present construction the sleeve 11 extends a relatively small distance beyond the annular chamber portion of the inlet 7, and is formed with an inwardly and downwardly beveled upper edge 17.

The Ipiston 8 is slightly reduced in diameter beginning at a point just above the piston ring 18 which latter is above and adjacent the ports 10, the reduced portion being of uniform diameter and having a packing` ring 1S adjacent its upper edge.

The upper portion of the valve bony is formed with a detachable section 19 and is securely attached by the cap screws 20, said section being suitably threaded to receive the threaded end of the conduit E. rlie section 19 carries the shoulder 14:, and is formed with an annular flange 20 of unifor n inner diameter to slidingly receive the reduced portionof the piston and its paci;- ing ring' 18, when the piston is-in its normal seated position. The annular flange is beveled to match the angularity of the beveled edge 17 of the sleeve 11 so as to tele scope into the latter. `As the inner diameter of the sleeve is uniform, a relatively small annular chamber Q1 is thereby formed, the latter surrounding the piston and extending, as shown, into open con'nnunication with the ports 13, so that the pressure in the live steam inlet 7 will prevail in said chamber. Thus, the pressure on the shoulder 2Q formed by the slight variation in the piston diameter, constantly holds the piston `to its seat.

ln operation, when the locon'iotive 'isdrifting and the steam supply is cut off, the piston will be actuated (in opposition to the pressure on the shoulder 2Q) by the bacia pressure in the cylinder, as stated in the foregoing, until it assumes the position indicated in Figure 3, in which position, steam is entering the cylinder through he conduit E, and the packing ring 18 is positioned at a point above the ports 13, thereby cutting off the steam supply for the chamber 21, and thereby relieving the piston of the downward pressure on the .shoulder Q2, thus facilitating the upward movement thereof as it approaches the shoulder 14. A clearance space 23 is provided at the top of the piston, from which space lead the radial ducts Q4, whereby pocleting of air or steam is prevented at that point which might otherwise retard the action of the piston. It will be noted that the shoulder 25 of the piston will arrive at the port 15 (in the downward movement ofthe piston) approximately at the same time that the top of the ring 18 will arrive at the upper edges of the ports 13, thereby enabling the pressure in the chamber 21 to be added to the force of'gravity due to weight of the piston in expelling (through the vent 16) air and steam from the cavity between the shoulders 9 and 9. The normal function of the port 15 and the duct 15a, Vin association with the cavity formed responsive to the movement of the piston, remains undis' turbed by the action of the steam pressure in chamber 21, except that the piston in its downward movement is slightly accelerated.

l claim:

1. A drifting valve, comprising a valve casing in open communication with a steam supply line, a differential valve member slid ably mounted in the casing, said valve having a drifting condition and a normal condition, means to close said supply line when the valve is in a normal condition, a passage in open communication with the casing and with the steam chest of an engine with which the device is to be associated, means to admit steam from the supply line to the steam chest of said engine when the valve is in a drifting condition, a steam by-pass opened by the operation of the valve to conduct steam from the steam supply line to an offset portion of the differential valve to sustain the valve in a drifting condition, and a chamber in open communication with said steam supply line when the vulve is in, a normal condtion, said chamber having a bottom formed by an oliset portion of tl e valve and a top formed by part of the casing toexert a downward pressure on the valve when ini-a normal condition.

2. A; drifting valve, comprising in combination a piston, slidably mounted in a tasing to have a normal and an operated position, said casing having a top, a bottom, and a sido opening, the top opening l'ieing connected .to a` steanr supply line during a power' operation of an engine with which the'drifting valve is associated, the bottom opening beingconnected to the compressive side of .said engine when the engine is drift ing, and the side opening being` connected to a steam supply line and being normally covered by the valve piston, the valve piston Y being shaped to uncover said side opening` when the valve piston is operated to bring said side opening into communication with the steam chest of the engine, and a chamber formed by an offset portion on the casing and on the valve piston to be in open communication with the side opening when the valve piston is in less than a fully operated position.

3. A drifting valve comprising a casing open to communication at its lower end with the cylinder of an engine and at its upper end with the steam chest thereof, a. ported member slidably mounted in the casing to have anormal and an operated condition, .said member being operated by pressure in the engine cylinder on Vthe compression side of its piston when the engine is drifting, a steam inlet in the casingl in the path of said ported member to register with the ports thereof when said device is operated, and means on the ported member and on the casing to be sealed from said steam inlet when said ported member is in an operated condition and to be in open communication with said steam inlet to form a downward propelling surface for the ported member when said ported member returns to a normal position. v

il. A drifting valve comprising a` casing` open to communication at its lower end with the cylinder of an engine with which the X drifting valve is associated and at its upper end with the steam supply line therefor, a ported member slidably mounted in the casing to have a normal and an operated condition, said member being operated by pressure in the engine cylinder on thecompression side of its piston when the engine is drifting, a steam inlet in the casing in the path of said ported member to register with the ports thereof when said device is operated to supply steam to the steam chest of the engine, and means on the ported member and on the casing to form an auxiliary dow wird propelling` surface acted upon by steam from said steam inlet when the ported member is in. less than :i ully operated condition.

EL drifting vulve comprising a easing in (pen eomn'mnieetion at one end with the eylincler of an engine with which the Valve is associated and at the other end with the steam chest ot' said engine and having a .teem inlet intermediately ot' seid easing, ek

portieri sliiuble member having a shoulder thereon mounted in the easing to have :i normal condition und an operated condition,

the sliilzible member noirnmllyv Closing the stemn inlet and being` operable by pressure in the ey inder when the engine is drifting to register seid ports with said steam inlet, a duet in the easing from said steam inlet to the interior of the casing above said shoulder, said duet beingl normally closed by the sliduble member and being opened by an operation of the slidable member to admit steam through said duct into Contact with the sliileble member below said shoulder' to impart :in upward movement thereto, and n chamber formed by an ollset portion on the slidable member and an offset portion on the easing, said chamber being in open communication with said live steam inlet during` :i return of the sliclable member lo normal.

In testimony whereof I ziliix my signeture.

HUGO F. RlPlEil. 

